• 자원리싸이클링
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• 제6권3호
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• pp.36-40
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• 1997

A series of processes has been developed to recover the gold from electronic scrap containing about 200~600 ppm Au. First, mechanical beneficiation including shredding, crushing and screening was employed. Results showed that 99 percent of gold component leaves in the fraction of under 1mm of crushed scrap and its concentration was enriched to about 800 ppm without incineration. The crushed scrap was leached in 50% aqua regia solution and gold was completely dissolved at $60^{\circ}C$ withing 2 hours. Other valuable metals such as silver, copper, nickel and iron were also dissolved. The resulting solution was boiled to remove nitrous compounds in the leachate. Finally, a newly designed electrolyzer was tested to recover the gold metal. More than 99% of gold and silver were recovered within an hour by electrowinning process.

• 대한금속재료학회지
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• 제48권3호
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• pp.241-247
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• 2010

In order to develop the vacuum distillation process of magnesium alloy scrap, a fundamental study on the evaporation behavior of magnesium alloy (AM50) scrap melt was carried out. Melt temperature, pressure, reaction time, and initial specific surface area of melt were considered as experimental variables. The evaporation rate of magnesium increased with the increase of melt temperature and initial specific surface area of melt, and with the decrease of the pressure. The activation energy of magnesium evaporation reaction calculated by an Arrhenius plot decreased with the decrease of the pressure and with the increase of the initial specific surface area of melt. An empirical equation was derived for the evaporation rate of magnesium from AM50 alloy melt.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3796-3798
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• 2011

• 한국구조물진단유지관리공학회 논문집
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• 제20권6호
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• pp.40-45
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• 2016

선반 스크랩은 금속 가공 공정에서 선반 및 밀링 작업에 의해 발생된 철강제품의 부산물이므로, 섬유보강 시멘트 복합체 제작시 이를 활용할 경우 경제성뿐만 아니라 환경 친화적인 효과를 가져온다. 따라서 이 연구의 목적은 강섬유 대체재료로서 선반 스크랩의 활용 방안을 제시하기 위하여 선반 스크랩 보강 시멘트 복합체(LSRCCs)의 작업성 및 강도 특성을 평가하는 것이다. 이를 위하여 금속 가공공장에서 3종류의 선반 스크랩을 채취한 후 폭 2 mm, 길이 40 mm로 가공하여 LSRCCs를 제작하였다. 그 결과, LSRCCs의 작업성은 플레인 모르타르보다 약간 저하되었고, 휨강도는 크게 개선되었으며, 선반 스크랩의 종류가 LSRCCs의 특성에 다소 영향을 미치는 것으로 나타났다.

• 자원리싸이클링
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• 제16권3호
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• pp.27-33
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• 2007

구리, 주석 등의 유가금속을 다량 함유하고 있는 폐전기전자 스크랩으로부터 유가금속을 회수하는 것은 자원 재활용 측면에서 매우 중요하다. 본 연구에서는 폐동슬래그를 슬래그 형성제로 활용하여 폐전기전자 스크랩으로부터 유가금속을 추출하기 위한 새로운 공정이 제시되었다. 제안된 공정은 슬래그 형성제로 동 제련소에서 배출되는 폐동슬래그를 재활용한다는 장점이 있다. 각 실험에서는 일정한 비율로 혼합된 폐전기전자 스크랩과 폐동슬래그의 혼합시료를 보조 슬래그 형성제인 CaO와 함께 고온 용융되었다. 실험 결과 폐전기전자 스크랩에 함유된 구리와 주석이 Cu-Fe-Sn 합금상으로 각각 95% 이상, 85% 이상 추출되었다.

• 복합신소재구조학회 논문집
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• 제6권2호
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• pp.70-76
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• 2015

It should be noted that the use of the lathe scrap for making fiber reinforced cementitious composites(FRCCs) raised friendly environmental effect as well as economy because the lathe scrap is a by-product of steel manufactures and is occurred when lathe and milling works of them are conducted to process steel manufactures. Thus, the purpose of this research is to investigate the effect of measurements of lathe scrap on the characteristics of FRCCs. For this purpose, various lathe scraps were collected from processing plants of metal, and then these were processed 10mm, 20mm, and 40mm in lengths for 2mm and 4mm in widths, respectively. FRCCs containing lathe scraps were made according to their widths and lengths, and then characteristics such as the workability, compressive strength, and flexural strength of those were evaluated. As a result, it was observed from the test results that the optimum measurements of the lathe scrap for manufacturing FRCCs was 2mm in width and 40mm in length.

• 자원리싸이클링
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• 제12권6호
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• pp.57-63
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• 2003

본 연구에서는 NdFeB 영구자석 스크랩으로부터 네오디뮴을 분리하고자 하였다. 네오디뮴과 철 성분을 추출하기 위하여 스크랩을 산화배소 한 후 황산침출을 수행하였으며, 황산침출 용액으로부터 황산나트륨을 사용한 복염침전법에 의하여 네오디뮴과 철을 분리하였다. 산화배소 시 온도는 소결자석 스크랩은 $500^{\circ}C$, 본드자석 스크랩은 $700^{\circ}C$가 적절하였으며, 황산침출 시 황산농도 2.0 M, 침출온도 및 시간 $50^{\circ}C$, 2시간 그리고 광액농도 15%에서 네오디뮴 99.4%, 철 95.7%를 회수할 수 있었다. 네오디뮴과 철의 최적분리조건은 황산나트륨 첨가량 2.0당량, 반응온도 $50^{\circ}C$이었으며, 이 때 네오디뮴의 회수율은 99.9% 이상이었다.

• 한국주조공학회지
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• 제40권3호
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• pp.85-96
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• 2020

The effect of an aluminum scrap addition ratio on the tensile and solidification cracking properties of the AC4A aluminum alloy in the as-cast state and heat-treated state were investigated in this study. Generally, the expected problem of using scrap in aluminum casting is an increase of hydrogen and Fe element inside the aluminum melt. Another issue is an oxide film which has a weak interface with the molten aluminum and acts as potent nucleation sites for internal porosity and crack initiation. Solidification cracking is one of the critical defects that must be resolved to produce high quality castings. A conventional evaluation method for solidification cracking is a relative and qualitative analysis method which does not provide quantitative data on the thermal stress in the solidification process. Therefore, a newly designed solidification cracking test apparatus was used in this study, and the device can provide quantitative data. As a result, after conducting experiments with different scrap addition ratios (0%, 20%, 35%, 50%), the tensile strengths and elongations in the as-cast state were 214, 187.7, 182.1 and 170.4MPa and 4.6%, 3.4%, 3.1% and 2.3%, respectively. In the case of the T6 heat-treated state, the tensile strengths and elongations were 314.9, 294.6, 293.1 and 271.1MPa and 5.4%, 4.6%, 3.8% and 3.1%, respectively. The strength of the solidification cracking was 3.1, 2.4, 2.2and 1.6MPa as the scrap addition ratio increases.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.230-235
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• 2001

There are more than 15 millions cars or motors in Taiwan. According to the statistics from Environmental Protection Administration, the number of resulting scrap tires are near 110 thousand tons each year. The tire recycle programs in Taiwan were first conducted in 1989 and executed by ROC Scrap Tire Foundation. However, the current efficiency of the tire recycling industry still needs to be improved to minimize the environmental problem or fire hazards caused by scrap tires storage. Ten major tire-recycling factories are surveyed in this study. The investigations include the source of scrap tire, the shredding process, the market of products, the management of wastes disposal, and the difficulties of these sectors. As the varieties of the shredding machines of the recycle factories, there are three kinds of final products which include powder, granular, and chips. The wastes, wires and fibers, produced by the shredding process are the major problems fur all the factories. The percentage of the wire and fiber removal from rubbers still needs to be increased. The best approaches found in this study to increase the efficiency of scrap tire recycling processes are proposed which include the improvement of magnetic separation system fiber/rubber separation system and the minimization of waste disposal. A categorized standard of the processing outputs is suggested as a reference for the decision-making of the tire-recycling factories.

• 자원리싸이클링
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• 제27권3호
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• pp.93-99
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• 2018

본 연구에서는 디스플레이 산업의 백금 폐스크랩을 용해, 용매추출을 통하여 백금족 성분을 효율적으로 추출하고, 추출된 백금용액을 디젤자동차 배가스 정화촉매용 전구체 용액으로서 제조하고, 그 촉매활성을 실험하였다. 용액화학적 이론 연구를 통하여 백금 화학종의 수용액상 거동을 조사하였고, 화학종들의 존재영역 및 거동을 근거로 추출 및 분리 가능방안을 수립하였다. 전기화학적 방법에 의해 폐스크랩을 용해시킴으로써, 용해시간 단축 및 추출효율을 높였으며, 로듐 성분을 분리 제거, TBP에 의한 용매추출, 염산에 의한 탈거 공정을 거쳐 Pt-Chloride-$H_2O$ 계 백금용액을 용액을 제조하고, 이 용액을 원료로 액상 아민화 반응을 통해 아민산 백금용액을 제조한 다음, 카본블랙의 연소반응에 대한 촉매 활성을 실험함으로써, 백금족 폐스크랩으로부터 고부가 백금족 화합물의 제조가능성을 연구하였다.